The present disclosure is directed to methods of generating an aqueous dispersion of crystalline polyester with a low degree of sulfonation for use in ultra low melt emulsion/aggregation (E/A) polyester applications. Additionally, this disclosure is directed to generating an aqueous dispersion process where low levels of sulfonated crystalline polyester resin is premixed in hot water followed by subsequent addition of a second polyester resin with a higher degree of sulfonation for use in ultra low melt E/A polyester applications.
Currently, aqueous dispersions can be generated by a process generally known as the solvent flash evaporation process. Solvent flash evaporation process is disclosed in U.S. patent application Ser. No. 10/778,557. In this process, the dispersion is created by dispersing resin in a volatile organic solvent. Volatile organic solvents include acetone, toluene, tetrahydrofuran, and the like. However, volatile organic solvents tend to be extremely volatile and explosions are possible. Thus, the solvent flash evaporation process must be conducted in an explosion proof environment.
Thus, there is a need to generate an aqueous dispersion having a small particle size and narrow size distribution under stable conditions without the use of such solvents.
Illustrated in U.S. Pat. No. 4,996,127 is a toner of associated particles comprising primarily particles of a polymer with acidic or basic polar groups, and which toners can be prepared by emulsion polymerization. In U.S. Pat. No. 4,983,488, there is disclosed a process for the preparation of toners by the polymerization of a polymerizable monomer dispersed by emulsification in the presence of a colorant and/or a magnetic powder to prepare a principal resin component, and then effecting coagulation of the resulting polymerization liquid in such a manner that the particles in the liquid after coagulation have diameters suitable for a toner. It is indicated in column 9 of this patent that coagulated particles of 1 to 100, and particularly 3 to 70, are obtained. Reference may also be made to U.S. Pat. Nos. 674,736, 4,137,188 and 5,066,560.
Emulsion/aggregation/coalescing processes for the preparation of toners are illustrated in a number of Xerox patents, the disclosures of which are totally incorporated herein by reference, such as U.S. Pat. Nos. 5,290,654, 5,278,020, 5,308,734, 5,370,963, 5,344,738, 5,403,693, 5,418,108, 5,364,729, and U.S. Pat. No. 5,346,797. Also of interest may be U.S. Pat. Nos. 5,348,832, 5,405,728, 5,366,841, 5,496,676, 5,527,658, 5,585,215, 5,650,255, 5,650,256, 5,501,935, 5,723,253, 5,744,520, 5,763,133, 5,766,818, 5,747,215, 5,827,633, 5,853,944, 5,804,349, 5,840,462, 5,869,215, 5,910,387, 5,919,595, 5,916,725, 5,902,710, 5,863,698, 5,925,488, 5,977,210 and 5,858,601.
The appropriate processes and components of these patents may be selected herein.